[senco-forum] timed reading comprehension group test for year 9

We have had to do this for current (and last year's) year 9 for exactly the
same reason.  We tried the Kirklees/Vernon Warden test first, but this year
we used Wordchains to screen the whole year group.  Although it tests
perception rather than understanding, Wordchains is very quick to mark (the
other one is tricky, having to subtract points for wrong answers).  We shall
use Wordchains again next year.

SS